The present invention relates to faucet aerators, and more particularly to such aerators manually selectable between spray and stream discharges. The term "aerator" includes nonaerating devices (e.g. laminar flow devices) as well.
In view of the need to conserve water consumption in many parts of the United States and the world, various devices for limiting water delivery on plumbing products are being developed and even mandated. Local and regional code agencies are specifying permissible water flow volumes (in gallons per minute [gpm]) on faucet aerators and shower heads. The maximum water flow presently permitted under most of these codes is now in the range of 2.0 to 2.5 gpm.
Even these restricted flows, however, may create wasteful consumption for a variety of applications, including hand washing, shaving, tooth brushing, other personal hygiene activities, and other water-using functions. Accordingly, some discharge devices have been developed, particularly for commercial applications (e.g. public washrooms) that deliver water at a much lower flow rate (e.g. 0.5 gpm) in a spray pattern. However, such devices are not practical for other applications requiring higher rates of flow.
In a separate development, two-stage aerators have also been designed to permit a user to manually select either a spray discharge or a stream discharge. Examples of such devices are illustrated in U.S. Pat. Nos. 3,706,418, issued Dec. 19, 1972 to Hyde; and 3,884,418, issued May 20, 1975 to Ritzenthaler et al. Both of these devices have a default stream flow position (aerator mode) and a manually selectable spray pattern position. The flow rates in both positions are approximately the same. Accordingly, these devices do not solve or even address water conservation issues except when equipped with additional restrictive devices that reduce flow equally in both modes.